The Internet Protocol (“IP”) serves as the de-facto standard for forwarding data messages (“datagrams”) between network devices connected with the Internet. To that end, IP delivers datagrams across a series of Internet devices, such as routers and switches, in the form of one or more data packets. Each packet has two principal parts: (1) a payload with the information being conveyed (e.g., text, graphic, audio, or video data), and (2) a header, known as an “IP header,” having the address of the network device to receive the packet(s) (the “destination device”), the identity of the network device that sent the packet (the “originating device”), and other data for routing the packet. Many people thus analogize packets to a traditional letter using first class mail, where the letter functions as the payload, and the envelope, with its return and mailing addresses, functions as the IP header.
When routing packets across a public or private network, there often is a risk that a person or device in that network may attempt to access and/or modify those packets. This problem has been variously described as the “man-in-the-middle” problem.